The FX series on AM2 always have 2 x 1 MB of L2 cache; the X2s sometimes have less. The FX chips have unlocked multipliers for overclocking. Those are the only differences.
If you only need to run one (not huge) monitor, get a motherboard with built-in video. If you need something a little fancier, get a cheap (sub-$50) passively cooled video card.